1. Field of the Invention
The present invention relates to an endoscope system that picks up an image of inside a subject using image pickup means.
2. Description of the Related Art
In recent years, an endoscope having an insertion portion that is insertable into a body cavity or the like has been widely used in medical fields and the like.
In the case of inserting the insertion portion into a luminal organ that branches in a complicated manner, such as bronchial tubes, within a body cavity to inspect (diseased tissue at) a target site at a distal end side of the luminal organ or to perform a biopsy or treatment using a treatment instrument, it is sometimes difficult to introduce the distal end of the insertion portion as far as the vicinity of the target site using only an endoscopic image that is obtained when the insertion portion is inserted.
Therefore, systems or apparatuses have been proposed that display images to support an operation to introduce the distal end of the insertion portion of an endoscope as far as the vicinity of a target site.
For example, as a first conventional example, Japanese Patent Application Laid-Open Publication No. 2011-189074 discloses a medical apparatus that includes: an insertion portion to be inserted into the bronchial tubes; a plurality of FBG sensor portions that are arranged in the insertion portion; a storage portion for storing previously acquired three-dimensional image data of the bronchial tubes; a shape measurement portion for measuring a shape of the insertion portion based on data of the FBG sensor portions; a core line calculating portion for calculating a core line of the bronchial tubes based on three-dimensional image data stored in the storage portion; and a position calculating portion for calculating a position of the insertion portion based on the shape that is measured by the shape measurement portion and the core line that is calculated by the core line calculating portion. The medical apparatus calculates a position and a direction of the distal end of the insertion portion by extracting the core line.
Further, as a second conventional example, Japanese Patent Application Laid-Open Publication No. 2012-24518 discloses a support apparatus that: acquires a central line of a tubular tissue (tubular organ) of a subject from a previously acquired three-dimensional image of the subject; displays an endoscopic image that was photographed while moving an endoscope that was inserted into the tubular tissue along the longitudinal direction of the tubular tissue; inputs a reference position of the endoscope at a time at which one feature region of the tubular tissue is shown in the displayed endoscopic image, and also sets a position corresponding to the one feature region on the central line; acquires a movement amount and a travelling direction of the endoscope when the endoscope has moved from the reference position; calculates a position that is at a distance corresponding to the acquired movement amount in the acquired travelling direction along the central line from the position corresponding to the one feature region as a current position; and displays an indicator representing the calculated current position on the central line. The support apparatus further calculates the position of image pickup means based on the core line of the tubular organ and a movement amount and a travelling direction of the image pickup means.
The aforementioned first conventional example discloses technology that is based on the viewpoint of calculating a position of a distal end of an insertion portion by extracting a core line, while the second conventional example discloses calculating the position of image pickup means (endoscope distal end) by means of a core line of a luminal organ and a movement amount and travelling direction of the image pickup means (endoscope distal end).